The present invention relates generally to a reinforced structural member for use in strengthening the stiffness and strength of a frame assembly. More particularly, the invention relates to a vehicle frame system of an automotive vehicle that is reinforced by a member coated over a portion of its surface with an expandable material, the combination of which increases the structural stiffness and strength of the automotive vehicle.
For many years the transportation industry has been concerned with designing reinforced structural members that do not add significantly to the weight of a vehicle. U.S. Pat. Nos. 5,755,486; 4,901,500; and 4,751,249 described prior art reinforcing devices. While these prior art devices may be advantageous in some circumstances, there is needed a simple low cost structure that permits coupling the reinforcement member to a variety of structures of varying geometric configurations. In the automotive industry there is also a need for a relatively low cost system for reinforcing automotive vehicle frame structures.
The present invention is directed to a structural reinforcement system, and particularly one for reinforcing automotive vehicle frame structures, such as (without limitation) vehicle roof and pillar structures. The system generally employs a skeleton member adapted for stiffening the structure to be reinforced and helping to redirect applied loads. In use, the skeleton member is in contact, over at least a portion of its outer surface, with an energy absorbing medium, and particularly heat activated bonding material. In a particular preferred embodiment, the skeleton member is a molded metal, or composite frame and it is at least partially coated with foamable epoxy-based resin, such as L5206, L5207, L5208 or L5209 structural foam commercially available from L and L Products of Romeo, Mich.
In one embodiment the skeleton member along with a suitable amount of bonding or load transfer medium is placed in a cavity defined within an automotive vehicle, such as a vehicle roof structure, pillar structure or both. The bonding medium is activated to accomplish expansion of the resin in the space defined between the skeleton member and the wall structure defining the cavity. The resulting structure includes the wall structure joined to the skeleton member with the aid of the structural foam.